Whenever I write ok the spell checkers underline it with a red line and suggest that I should OK. Not even Ok works. Why is that?

  • 1
    It’s a bug in your spellchecker. Just add the word to your dict list.
    – tchrist
    Commented Mar 22, 2013 at 14:31
  • 1
    @tchrist well its in Gmail. So its not my spell checker Commented Mar 22, 2013 at 16:58
  • If its gmail, that's most likely your web browser doing the spellcheck, not Google.
    – T.E.D.
    Commented Nov 26, 2013 at 19:37
  • @tchrist: Since this is english.SE, I'll be that guy...It's not a bug when a word isn't in the list, and in this case, it might even be absent for a reason. See the answer on the original, and upvote it! Commented Jan 29, 2014 at 8:27

3 Answers 3


OK is Ok, and Ok is OK.

Oh, also Oklahoma is OK. That's its USA postal code, so it's possible that your spell-checker is agnostic on the subject, and just thinks you are trying to use the state of Oklahoma in an address.

I upvoted @camelbrush's answer because it provides a good explanation of the logic behind why some folks prefer to capitalize both letters. However, nobody is really sure where this word came from. Wikipedia has a table of around 30 of the more popular theories (from 13 different languages).

Realistically one just has to accept that both are in common use, and neither is provably "wrong". If the uncertainty really bugs you, just use the word "Okay" instead.

  • Here are a few other theories : thefictiondesk.com/blog/ok-or-okay
    – camelbrush
    Commented Mar 22, 2013 at 15:46
  • 1
    Here's a theory that "ok" and "Ok" are not OK. +1 for the link to Wikipedia's proposed etymologies though! Too much false certainty going around on this question. Commented Jan 29, 2014 at 8:30
  • I think it is problematic that there are two different accepted answers to this question on these boards (as Nick Stauner remarks, the question that this one is marked as a duplicate of, has an accepted answer saying that "OK" is the only valid spelling). I am inclined to disagree with T.E.D.: Although there are competing theories as to the origin of "OK", most (or all?) of them agree that it is an initialism, in which case all style guides seem to agree it should be uppercase. The only argument for "ok" is the descriptivist one: People do use it.
    – Nagel
    Commented Jul 31, 2014 at 10:30
  • @Nagel - Not true. Of the three theories that Wikipedia bothered to explain out on their main Okay page (helpfully liked above), only one is an abbreviation. Not that I think that matters much. The question is about practice, not history. In practice, there is no authoritative answer, and both can be (and are) used.
    – T.E.D.
    Commented Jul 31, 2014 at 11:40
  • @Nagel - Oh, and as for there being two "disagreeing" answers on supposedly "exact duplicate" questions, that's perhaps at least partially because the questions aren't in fact exact duplicates. This question is asking about capitalization, while the other was asking if there was any difference in meaning between the various forms found in the wild. The problem there IMHO is with folks who are overanxious to close questions, not with either answer. God save us all from the chaos that will ensue when some helpful person decides to merge the answers in these 2 supposedly "identical" questions.
    – T.E.D.
    Commented Jul 31, 2014 at 11:49

OK is an abbreviation. This is what Oxford online dict says about its origin:

mid 19th century (originally US): probably an abbreviation of orl korrect, humorous form of all correct, popularized as a slogan during President Van Buren's re-election campaign of 1840 in the US; his nickname Old Kinderhook (derived from his birthplace) provided the initials

Now, let us look at this style guide about capitalization (Guardian Style Guide):

Use all capitals if an abbreviation is pronounced as the individual letters: BBC, VAT, etc; if it is an acronym (pronounced as a word) spell out with initial capital, eg Nasa, Nato, unless it can be considered to have entered the language as an everyday word, such as awol, laser and, more recently, asbo, pin number and sim card. Note that pdf and plc are lowercase.

Here is another style guide that suggests:

Pronounceable abbreviations
Abbreviations that can be pronounced are usually acronyms, ie, words formed from or based on the initial letters or syllables of other words, such as radar, NATO, UNESCO. These are not normally preceded by the definite article.

But then, different office suites (MS Office, Libre Office, Lotus, etc) imply these rules differently. MS Office accepts both Ok and OK.


The word is usually written OK or okay as it is a verbalization of the letters O and K, and that is simply the accepted spelling.

If I were to read ok or Ok somewhere, I would think it a misspelling of auk.

  • 3
    If I were to read ok or Ok somewhere, I would certainly not think it a misspelling of auk! I would think it meant OK.
    – camden_kid
    Commented Mar 22, 2013 at 14:40
  • I might think of Oklahoma.
    – GEdgar
    Commented Mar 22, 2013 at 14:41
  • i wonder why the down vote? cause of suggesting auk?
    – camelbrush
    Commented Mar 22, 2013 at 14:43
  • 2
    @GEdgar In lowercase? At best, a typo for oak.
    – choster
    Commented Mar 22, 2013 at 14:43

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